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C / Unicode limited to Plane 0 (U+0000 to U+FFFF) in (C)SFML?

« on: July 12, 2022, 12:25:37 pm »

Hi,

I started with CSFML a couple of weeks ago.
I am *not* using SFML but only the C binding, so questions and reports here may or may not also apply to SFML itself.
I just don't know, :-).

When I came to unicode strings I first had to manage some hurdles as my programs(s) should run in a Windows an a Linux enviroment, and handling the locales and wide characters is not alway funny then.
Especially, I miss the UTF_X_toUTF_Y conversion functions in the C binding.
You may consider to add them in a future release ...
But of course, this can also manually be done.

But when I wanted to set a unicode string to an sfText ('sfText_setUnicodeString()') I had to realize that CSFML doesn't accept unicode characters on higher planes beyond U+FFFF.

So I decided to get the character by the font itself (see example below) - same result.

Good for testing is the unicode font 'unifont' from  https://www.unifoundry.com/unifont/index.html that virtually contains an image for (nearly) every single code point.

My 'test character' is U+1D11E ('Musical Symbol G Clef') but you'll find that no unicode character at all will work in (C)SFML beyond 'U+FFFF'.

Is this a bug or by design? But if it's by design - why use 4 byte long sfUint32 integers to handle them ...?

 

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <SFML/Graphics.h>


sfRenderWindow* window;

void selectGlyph(void *data)
{
        sfUint32 *codePoint = data;
        char buffer[8];

        while(sfRenderWindow_isOpen(window))
        {
                printf("Enter hexadecimal code point: ");
                do
                {
                        fgets(buffer, 8, stdin);
                } while (strcspn(buffer, "\n") == 7);
                *codePoint = strtoul(buffer, NULL, 16);
        }
}

int main(void)
        {
        sfVideoMode mode = {160, 160, 32};
        sfTexture* texture;
        sfSprite* sprite;
        sfEvent event;
        sfColor bColor;
       
        sfUint32 codePoint = 0x0000;
        sfUint32 oldCodePt = 0xFFFF;
        sfThread *thread = sfThread_create(selectGlyph, &codePoint);
       
        /* Create the main window */
        window = sfRenderWindow_create(mode, "CSFML Unicode Test", (sfDefaultStyle), NULL);
        if (!window)
                return EXIT_FAILURE;
        sfRenderWindow_setVerticalSyncEnabled(window, sfTrue);
        sfRenderWindow_setPosition(window, (sfVector2i){50, 50});
        /* Create a graphical text to display */
        sfFont *font = sfFont_createFromFile("unifont-14.0.04.ttf");
        if (!font)
                return EXIT_FAILURE;
        unsigned int size = 160;
       
        sfThread_launch(thread);
       
        /* Start the game loop */
        while (sfRenderWindow_isOpen(window))
        {
                /* Process events */
                while (sfRenderWindow_pollEvent(window, &event))
                {
                        /* Close window : exit */
                        if (event.type == sfEvtClosed)
                                sfRenderWindow_close(window);
                }
               
                if(codePoint != oldCodePt)
                {
                        sfGlyph glyph = sfFont_getGlyph(font, codePoint, size, sfFalse, 0);
                        const sfTexture *bitmap = sfFont_getTexture(font, size);
                        if (!bitmap)
                                return EXIT_FAILURE;
                        sfImage *chr = sfTexture_copyToImage(bitmap);
                        if(glyph.bounds.width > 0 && glyph.bounds.height > 0)
                        {
                                sfImage *image = sfImage_create(glyph.bounds.width, glyph.bounds.height);
                                sfImage_copyImage(image, chr, 0, 0, glyph.textureRect, sfFalse);
                                texture = sfTexture_createFromImage(image, NULL);
                                if (!texture)
                                return EXIT_FAILURE;
                                sprite = sfSprite_create();
                                if (!sprite)
                                        return EXIT_FAILURE;
                                sfSprite_setColor(sprite, sfBlue);
                                sfSprite_setTexture(sprite, texture, sfFalse);
                                oldCodePt = codePoint;
                                bColor = codePoint ? sfYellow : sfRed;
                        }
                        else
                                codePoint = 0;
                }
                sfRenderWindow_clear(window, bColor);
                /* Draw the sprite */
                sfRenderWindow_drawSprite(window, sprite, NULL);
                /* Update the window */
                sfRenderWindow_display(window);
        }
        /* Cleanup resources */
        sfThread_destroy(thread);
        sfSprite_destroy(sprite);
        sfTexture_destroy(texture);
        sfFont_destroy(font);
        sfRenderWindow_destroy(window);
        return EXIT_SUCCESS;
}